CVE-2026-128238 · Package
NO FIX YET · SEE WHAT TO DO
Scapy's BER/ASN.1 decoder recurses without a limit, so a single crafted packet with 250 nested SEQUENCE structures raises an unhandled RecursionError. An unauthenticated remote attacker can crash any application that parses TLS, SNMP, X.509 or LDAP data through Scapy.
first public Sep 8, 2026 · 1 source
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Applications that use Scapy's ASN.1/BER decoder on packets from untrusted networks, such as TLS, SNMP, X.509 or LDAP parsing, are exposed. Projects that only use Scapy offline on trusted captures or never decode ASN.1 from the network can likely skip it. The sources do not say whether the crash can be avoided through the safe=True option, beyond noting that it does not prevent the crash.
Not affected if no-untrusted-input, scapy-not-used
Who cares network-tools, python, scapy
pip show scapy or python -c "import scapy; print(scapy.VERSION)", and treat anything below 2.8.0 as affected.scapy in requirements files, lock files or the output of pip freeze.2.8.0 or later.Scapy before 2.8.0 contains an uncontrolled recursion vulnerability in the BER/ASN.1 decoder in scapy/asn1/ber.py that allows unauthenticated remote attackers to crash parsing applications. Attackers can send a single 833-byte packet with 250 nested ASN.1 SEQUENCE structures to trigger an unhandled RecursionError, terminating TLS, SNMP, X.509, or LDAP parsers even with safe=True.
This page as .md · .json · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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